Relay counting chain



June 4, 1968 H. P. BOSWAU RELAY COUNTING CHAIN Filed Jan. 14, 1965 2 Sheets-Sheet 2 R J J .b 4 3 W. .H 4 I l 4 4 A 1 1 1 I I 1 l 3 n 0 l m F m Q n M United States Patent 3,387,186 RELAY COUNTING CHAIN Hans P. Boswau, Los Altos, Calif., assignor to Automatic Electric Laboratories, Inc., Northlake, 11]., a corporation of Delaware Filed Jan. 14, 1965, Ser. No. 425,385 8 Claims. (Cl. 317-140) ABSTRACT OF THE DISCLOSURE A two-relay bistable circuit module in which only a single make contact per relay is required for the control of the relay windings-an operating winding and a differential winding in the case of the first relay, and an operating winding and a hold winding in the case of the second relay-and on which the circuit for the energi- Zation of the operating winding of the first relay is independent of contacts of both relays and hence is closed from beginning to end of each pulse. Because of its contact economy this module is of particular advantage if it is made up of reed relays. Only three bistable modules of the above general kind are needed to form a decimal counting chain. In such a counting chain the single make contacts of the second relays are used to advance the input circuit to the next succeeding module. Also in such a counting chain the single make contacts of the various relays may be further used for controlling a readout circuit.

This invention relates in general to counting chains and in particular to relay counting chains employing reed relays as switching elements.

Counting chains are well known in the art. They usually comprise several stages of bistable devices. Where extremely high counting speed is required, solid state components are usually used in the individual stages. In some applications, however, extremely high counting speed is not essential, and reed type relays can be advantageous-. ly used as components in the individual stages.

Therefore, it is an object of this invention to provide an improved and simplified bistable circuit module.

It is a further object of this invention to provide an improved and simplified relay counting chain composed of a plurality of bistable circuit modules.

This invention features a bistable circuit module which employs a pair of two winding reed relays with differential windings on one of the relays and which uses only one normally open contact pair of each relay in the operating circuit of the module.

The invention also features a decimal counting chain in which only three bistable circuit modules are employed, the final module having a local circuit on one of its relays for the purpose of maintaining that relay in an operated condition after its initial operation and in dependently of the pulses received by the module.

Other objects and features of this invention will be apparent from a reading of the following detailed description of a particular embodiment in conjunction with the accompanying drawings, in which:

FIG. 1 is a circuit drawing of a decimal counting chain showing the individual bistable circuit modules of which the chain is comprised.

FIG. 2 is a pulse chart showing the operation of the relays of the counting chain of FIG. 1.

FIG. 3 is a circuit drawing of a particular type of readout apparatus for use in conjunction with the decimal counting chain of FIG. 1.

Referring specifically to FIG. 1, the decimal counting chain is comprised of bistable circuit modules 10, 11, and 12. Bistable circuit module is comprised of a pair of relays 110 and 120, each having an upper winding and a lower winding. The lower winding of relay 110 is an operating winding, while the upper winding of relay 110 is a differential winding. Therefore, when only one winding is energized, the relay is operated; but when both windings are energized together, the relay is in an unoperated condition. Relay 110 has a normally open contact pair 111 employed in the operating circuit of the circuit module 10.

The lower winding of relay 120 is an operating winding, while the upper winding of relay 120 is a hold winding. Therefore, when either or both of the windings are energized, the relay is in an operated condition. Relay 120 has one normally open contact pair 121 employed in the operating circuit of the module 10.

The input terminal 2% is connected to a source 13 of pulses at ground potential. The series circuit connection for the upper windings of relays 110 and 120 is completed between negative battery and the input terminal 20 by way of the normally open contact pair 121 of relay 120. The circuit connection for the lower winding of relay 110 is completed between negative battery and the input terminal 20 independently of the normally open contactpair 121 of relay 120. The series circuit connection for the lower windings of relays 110 and 120 is completed between battery and ground by way of the normally open contact pair 111 of relay 110. The diode D1 being a unidirectional current conducting means, is connected between the input terminal 20 and the junction 31 between the lower winding of relay and the series combination of the lower winding of relay 120 and the normally open contact pair 111 of relay 110.

The operation of the bistable circuit module 10 is as follows. Upon receipt of the first pulse at input terminal 29, the only complete circuit is the one to the lower winding of relay 110. Relay operates closing its contacts 111 to prepare a circuit for the lower winding of relay but relay 120 does not operate during the first pulse because it is shortcircuited by ground potential at junction 31.

Upon the cessation of the first pulse, the ground potential at junction 31 is removed, and the lower winding of relay 120 is energized in series with the lower winding of relay 110. Relay 120 operates and relay 110 holds operated during the interval between the first and second pulses. The operation of relay 120 closes the contact pair 121 to prepare a circuit for the upper windings of relays 119 and 120; but neither of these windings is energized since no pulses are being received at the input terminal 2t), and the diode D1 blocks the feed-back of current from the junction point 31 to the input terminal 20.

Upon receipt of a second pulse, the upper windings of relays 110 and 120 are energized. The lower Winding of relay 110 is also held energized, but the lower winding of relay 120 is short circuited. Since both the lower, operating Winding of relay 110 and the upper, differential winding of relay 110 are energized together, relay 110 is released and the contact pair 111 is opened, opening the circuit to the lower winding of relay 120. Relay 120 however, is held operated on its upper winding. Thus, during the second pulse, relay 110 is released while relay 120 is held operated.

Upon the cessation of the second pulse, the upper Winding of relay 129 is de-energized. Relay 120 releases, opening contact pair 121, and the module is back in its original state before any pulses were received.

The circuit of the bistable circuit module 11 is identical with that of bistable circuit module 10, so the operation of module 11 is identical with that of module 10. By connecting module 10 and module 11 together, a counting chain capable of counting four pulses in a binary fashion is produced. The interconnection of modules 10 and 11 is accomplished by connecting input terminal 21 of module 11 to input terminal 20 of module by way of the normally open contact pair 121 of relay 120 in module 10. The operation of the resulting two stage counting chain is as follows.

Upon receipt of the first pulse at input terminal 20 of module 10, only the lower winding of relay 110 is energized. The pulse does not reach the input terminal 21 of module 11 because contact pair 121 is open. Relay 110 operates on its lower winding, and contact pair 111 closes to prepare a circuit for the lower winding of relay 120.

Upon cessation of the first pulse, the lower winding of relay 120 is energized in series with the lower Winding of relay 110, so that relay 120 operates and relay 110 holds operated during the interval between the first and second pulses. The operation of relay 120 closes the contact pair 121 to prepare circuits for the upper windings of relays 110 and 120 and for the lower winding of relay 130.

Upon receipt of the second pulse at input terminal 20, the upper windings of relays 110 and 120 are energized. The lower windings of relays 110 and 130 are also energized because of the appearance of ground potential at junction points 31 and 32, while the lower windings of relays 120 and 140 are short circuited by that ground potential. Since both windings of relay 110 are energized, relay 110 is released and contact pair 111 is opened, opening the circuit to the lower winding of relay 120. Relay 120, however, is held operated on its upper winding; and relay 130 operates on its lower winding. The operation of relay 130 closes the contact pair 131 to prepare a circuit for the lower winding of relay 140.

Upon the cessation of the second pulse, the upper and lower windings of relay 110 are de-energized without effect since the relay was already released. The upper winding of relay 120 is also de-energized, causing relay 120 to release and contact pair 121 to open. The ground potential disappears from junction point 32 and the lower windings of relays 130 and 140 are energized in series. Relay 140 operates and relay 130 is held operated during the interval between the second and third pulses. The operation of relay 140 closes contacts 141 to prepare a circuit for the upper windings of relays 130 and 140.

Relays 130 and 140 are held operated on their lower windings during the interval between the first and the second pulses which arrive at input terminal 21 of module 11. The third pulse received at the input terminal 20 of module 10 does not appear at the input terminal 21 of module 11 since contact pair 121 is open. Therefore, it does not affect the states of module 11, and relays 130 and 140 hold operated. However, with the receipt of the third pulse at input terminal 20, the operation cycle of module 10 begins with the energization of the lower winding of relay 110 and the consequent operation of that relay. During the interval between the third and fourth pulses received at the input terminal 20, relay 120 operates on its lower winding and relay 110 holds operated on its lower winding. Also, relays 130 and 140 hold operated on their lower windings.

Upon receipt of the fourth pulse at input terminal 20, relay 110 releases, and relay 120 holds operated on its upper winding. Since contacts 121 are closed, the fourth pulse appears at input terminal 21 of module 11 as the second pulse to be received by that module. The upper windings of relays 130 and 140 are energized. However, since both windings of relay 130 are energized, that relay releases, while relay 140 holds operated in its upper winding.

Upon the cessation of the fourth pulse, all previously energized windings are de-energized, and the counting chain is back to its condition before the first pulse was received.

It is apparent that any number of additional modules which are identical to modules 10 and 11 could be added to the counting chain to enable it to count a higher number of pulses in a binary fashion. Four stages would be required to count to 10. However, it is possible to construct a three module chain capable of counting to ten in a decimal fashion by adding certain features to the third or terminal module in the counting chain. Module 12 in FIG. 1 has these additional features.

The circuit of module 12 is substantially the same as the circuit of modules 10 and 11. The series circuit connection for the lower windings of relays 150 and 160 is completed between battery and ground by Way of the normally open contact pair 151 of relay 150. The series circuit connection for the upper windings of relays 150 and 160 is completed from negative battery to the input terminal 22 by way of the normally open contact pair 161 of relay 160. However, in module 12, the normally open contact pair 161 is introduced between the upper winding of relay 160 and the upper winding of relay 150, and a local circuit consisting of a resistance path through resistor R to ground, is introduced at the junction between the normally open contact pair 161 and the upper winding of relay 150. Diode D3 is introduced between the upper winding of relay 150 and the input terminal 22 to block the feedback of current from resistor R through the upper winding of relay 150 to the lower winding of relay 15s or back to other portions of the counting chain. The local circuit provides a complete path between battery and ground for the upper winding of relay 160 when contact pair 161 is closed, so that relay 160 is locked operated over the local circuit after the relay 160 operates initially on its lower winding.

The operation of module 12 is similar to the operation of modules 10 and 11 except that, because of the local circuit for the upper winding of relay 160, relay 160 does not release after the cessation of the second pulse received at input terminal 22 of module 12, but continues to hold operated during successive pulses. The pulse chart of FIG. 2 shows the operation of the decimal counting chain of FIG. 1. Module 10 operates as previously described, completing one cycle of operation every two pulses. Module 11 operates as previously described, beginning its operation cycle on the second, sixth, and tenth pulses, and terminating its cycle on the fourth and eighth pulses. Module 12 begins its operation cycle on the fourth pulse and terminates it cycle on the eighth pulse, but relay 160 continues to hold operated through the tenth pulse because of the local circuit. The three module chain is able to count ten pulses since, as can be seen from the pulse chart in FIG. 2, different combinations of relays are operated during the intervals between the pulses, received by the chain.

Lead 41 in module 10 is connected at junction point 31. The appearance on this lead of resistance-battery during any particular interval between pulses indicated that relay is in an unoperated condition. The appearance on lead 41 of resistance-ground indicates that relay 110 is in an operated condition. Similar marks appear on leads 42 and 43, which are connected, respectively, to junction points 32 in module 11 and 33 in module 12 to indicate the state of relays and 150. Lead 44 in module 12 is connected to junction point 34. The presence on lead 44 of resistance-battery indicates that relay 160 is not operated. The presence on lead 44 of resistance-ground indicates that relay 160 is operated. Since the marks appearing on leads 41 through 44 indicate the state of the four relays 110, 130, and during any particular interval between pulses, and since during each particular interval a unique combination of these relays are operated, leads 41 through 44 can be connected to a read-out circuit such as is shown in FIG. 3. The read-out circuit being capable of indicating the number of pulses counted by the counting chain in a one-out-of-ten or two-out-of-five fashion.

Since it is desirable to be able to reset the counting chain after it has counted a certain number of pulses, some means must be provided in the operating circuit of the counting chain to open the circuits to the operated relays after any particular pulse has been received. Normally-closed hook switch contacts 23, 24, and 25 permit this resetting operation since operation of the hook switches would remove the ground potential from the windings of all relays which might be operated during any particular interval between pulses. This resetting operation could also be accomplished with a number of con tacts on one hookswitch or by a relay which would operate in response to a signal from other equipment.

By virtue of the present invention, a bistable circuit module is produced which utilizes only one diode and one normally-open contact pair on each of the said relays in the operating circuit of the module. No additional contact pairs are needed when one bi-stable circuit module of this type is hooked to one or more other cirof relay 120 to ground at key 23. After relay 110 has re leased due to ground being simultaneously applied to both of its windings during each even pulse, direct ground is connected to terminal 41 by way of diode D1 throughout the remainder of the pulse; as a result the ampere turns developed by the upper winding of relay 440 exceed those developed by the lower winding of this relay due to ground continuously applied thereto through contact 411 of relay 410, and hence the relay, with its windings no longer in balanced condition, will operate. In this fashion only resistance ground but not direct ground on terminals 41, 42, 43 or 44 is effective to prevent operation of the corresponding differential relay or relays.

CHART A Terminals Marked Relay Windings Leads Marked Digit 440 450 460 480 41 42 43 44 420 430 470 1 of 2 of 5 U L U L U L U L Notes.-X=terminal marked with resistance ground; +=relay winding energized; 0=relay winding not energized.

cuit modules to form a counting chain, because one of the normally-open contact pairs on the first module operates to transfer the count to the second module and so on down the line in the counting chain. The simplified construction of the bi-stable circuit module also permits the construction of a relay counting chain which employs only three such modules. Only the terminal module need be modified to include a local circuit for holding one of its relays operated beyond the cessation of the second pulse received by that module. It is the addition of the local circuit which eliminates the need for a fourth stage or module because, by keeping relay 160 operated after the cessation of the eighth pulse received at input terminal 20, the combinations of relays operated during the interval between the ninth and tenth pulses and the interval after the tenth pulse is difierent from the combinations of relays operated during the interval between the first and second pulses and between the second and third pulses, as can be seen from the operation chart of FIG. 2.

FIG. 3 illustrates a readout circuit which is designed to be connected to terminals 41 through 44 of the relay counting chain of FIG. 1. As shown, contact trees can be devised to enable the readout circuit to indicate the number of pulses counted in a one-out-of-ten or a two-cuboifive manner. The operation of the readout circuit of HG. 4 can bestbe understood from Chart A below.

This readout circuit can be used in common with several counting chains, so relay 410 having normally open contacts pairs 411 through 415 is shown to indicate that the readout circuit can be selectively connected to a number of counting chains.

Chart A is largely self-explanatory but the following discussion will be helpful in the understanding of the operation of differential relays 440, 459, 46!} and 480: The windings of these diiferential relays are dimensioned so that the ampere turns developed by a given winding pair cancel out when resistance ground is connected to terminals 41, 42, 43, 44 so that the relay i kept from operating. Taking, for example, the case of terminal 41, resistance ground is applied to this terminal when the lower winding of relay 110 is connected in a holding circuit extending through contact 111 and the lower winding While a particular embodiment of the invention has been described it is to be understood that many modifications could be made without departing from the spirit and scope of the invention as claimed.

What is claimed is:

1. A bistable circuit module of the type which completes one cycle of operation for every two input pulses received, said module comprising a first and a second relay each having first and second windings and a pair of normally open contacts; a diode; a first-potential terminal; a second-potential terminal; an input terminal for receiving a train of operating pulses of said first potential;

a first series combination of said diode and said first winding of said first relay; a second series combination of said contacts on said first relay and said first winding of said second relay; a third series combination of said second winding of said first relay, said second winding of said second relay, and said contacts on said second relay; said first series combination and said third series combination connected in parallel between said input terminal and said secondpotential terminal in a manner such that said diode in said first series combination is between said input terminal and said first winding of said first relay and is in a conducting state during the on portion of each pulse, and such that said first and second windings of said first relay oppose each other when energized together; said second series combination connected between said first-potential terminal and a junction point between said diode and said first winding of said first relay such that said first and second windings of said second relay aid each other when energized together.

2. A bistable circuit module having an input terminal connected to a source of pulses and comprising a pair of relays each having an operating winding and another winding and having contacts controlling the energization of said windings, said windings and contacts being connected so that said first relay is operated and released upon the receipt of a first and a second pulse respectively, and said second relay is operated upon the termination of said first pulse and then held operated for a time interval including the period between said pulses and the duration of said second pulse, wherein the improvement comprises:

that each said relay (e.g. 110, 120) has only a single pair of contacts (111, 121) for the control of said windings, said single contact pair of each said relay being normally open;

that said module includes a first circuit which extends from said input terminal (20) to the operating winding of said first relay (110), and is independent of contacts of both said relays and hence is closed from beginning to end of each said pulse, said first relay being operated in said first circuit and then locally held by way of said single winding-controlling contact pair (111) of said first relay; and a second circuit for energizing the other winding, being a holding winding, of said second relay (110), thereby to hold said relay after having operated in response to termination of said first pulse, and for energizing the other winding, being a differential winding, of said first relay (110), thereby to release said relay, said second circuit, being completed by way of said input terminal (20) at the beginning of the second pulse concurrently with said first circuit and remaining closed by way of said terminal, together with said first circuit, for the duration of said pulse whereby said first relay (110) is held released throughout said pulse.

3. A bistable circuit module as claimed in claim 2, wherein said module includes a third circuit extending serially over the operating windings of both said relays and over said single winding-controlling contact pair (111) of said first relay (110), said circuit being prepared when said first relay (110) operates upon receipt of said first pulse and being made effective upon termination of said pulse to hold said first relay and allow said second relay (120) to operate.

4. A bistable circuit module as claimed in claim 3, wherein a unidirectional current conducting means (D1) is connected between said input terminal (20) and the junction (31) between the operating winding of said first relay (110) and the series combination of said operating winding of said second relay (120) and said contact pair (111) of said first relay (110) to prevent feedback of current to said differential winding of said first relay (110) between the first and second pulses.

5. A counting chain arrangement comprising a plurality of bistable circuit modules as claimed in claim 2, wherein the relays of each said pair are encapsulated-reed relays; wherein said input terminal (20) of the first of said modules (10) is connected directly to said source of pu1ses ('13); and wherein said input terminal (21, 22) of each succeeding module (11, 12) is connected to the input terminal of the immediately preceding module by way of said contact pair of said second relay of said immediately preceding module.

6. A decimal counting chain arrangement comprising two initial modules (10, 11) and a terminal module (12), as claimed in '5, wherein said second relay 1(160) of said terminal module in operating completes at its said contact pair (161) an alternate holding circuit which is independent of the input terminal (22) of said module (12), so that said other winding of said second relay (160) remains energized after the termination of the second pulse received by said module.

7. A decimal counting chain arrangement as claimed in claim '6 and comprising readout apparatus ('FIG. 3) for indicating the number of pulses counted by said counting chain, wherein output circuit connections (41, 43, 43, 44) are provided for the control of said readout apparatus from said counting chain (FIG. 1), said output circuit connections being controlled by said contact pair (111, 131, 151) of said first relays (110, 130, of each said module (10, 11, 12) and by said contact pair (161) of said second relay of said terminal module :(12) of said chain.

8. A decimal counting chain arrangement as claimed in claim 7, wherein said readout apparatus is associated in common with a plurality of said decimal counting chains and wherein there are provided means for selectively connecting said output circuit connections of one of said counting chains to said readout apparatus.

References Cited UNITED STATES PATENTS 2,593,578 4/1953 Liberg 317- 140 2,636,932 4/ 1953 Oberman et al, 317-140 3,017,542 l/1962 Pearce 317-140 3,067,363 12/ 1962 Fleckenstein 317140 3,244,942 4/ 1966 Deeg.

LEE T. HIX, Primary Examiner. 

